First Battle of Nordlingen

The First Battle of Nordlingen was a major battle of the Thirty Years War that took place on 6 September 1634, in present-day Bavaria, Germany. Gustav Horn's Swedish, Saxon, and western German army of 25,600 troops that had invaded Bavaria were encountered by the cousins Cardenal-Infante Fernando de Espana and Ferdinand of Hungary and a combined Spanish-Imperial-Bavarian army of 34,000 troops. The result was a successful tercio attack, which decimated the Swedish army and temporarily turned the tide of the war.

History
After the death of Gustavus Adolphus, the Swedish campaign lost its strategic direction at precisely the time the Catholic camp became more united. Wallenstein's dismissal as commander helped heal a rift between the Imperial and Spanish branches of the Habsburgs. In September 1634 their combined army moved into Bavaria. Their encounter with the Swedish army at Nordlingen was characterized both by extraordinary bravery and great confusion. The Imperial and Spanish troops occupied the flatter ground in front of the town, with the vanguard on a hill commanding the road. The Swedish army took up position on a series of low hills one mile to the southwest. The Protestants planned to attack at daybreak simultaneously in the valley and on the hill, but fatally, their commanders did not consider the woods, which rendered the coordination of their armies nearly impossible. The battle descended into a series of intense but confused confrontations. At one point two brigades of Swedish infantry fired on each other. Isolated and eventually overcome, the Swedish forces were butchered. With Habsburg success threatening Europe with the specter of "universal monarchy", France entered the Thirty Years War.